Quantum Public-Key Cryptosystem with Reusable (Public Key Privtate Key) Pair Using the Bell States

In most of the traditional quantum public-key cryptosystems the public key held by the key management center (KMC) is a group of quantum systems. The public key will be destroyed after a secret communication process. So users must reconstruct the public key with KMC after every communication process or keep many copies of public key in the beginning. It’s an obstacle for the quantum cryptosystem to apply in practice. A quantum public-key cryptosystem with reusable (public key privtate key) pair using the bell states is provided in this paper. Every user shares a set of entangled quantum systems in the Bell states with KMC as his or her (public key, private key) pair. Two users can acomplish secret comminications by the help of KMC. Moreover the states of the quantum systems turn back to their original states. The user’s (public key, private key) pair is unchanged so that they are reusable. It’s unnecessary for users to reconstruct the public key with KMC or save many copies of public key in KMC. So this public-key cryptosystem is of much lower management expenses. It’s easier to realized in practice than most of traditional quantum public-key cryptosystems.